To keep green bean soup bright green, try the following: boil quickly, don't overcook, add acidic ingredients, don't add alkaline ingredients, and cool quickly.

1, quick boil: Before cooking green bean soup, quickly boil the green beans in boiling water for one to two minutes. This will help keep the color of the green beans bright.

2, don't overcook: Try to avoid overcooking the green beans once they are cooked. Overcooking will cause the green beans to become dull and lose their bright green color. When cooking green bean soup, you can control the cooking time, cook until the green beans become soft and rotten.

3, add acidic ingredients: in cooking green bean soup, you can add some acidic ingredients, such as lemon juice or vinegar. Acidic ingredients can help maintain the color of the green beans and prevent them from discoloration.

4, do not add alkaline ingredients: avoid adding alkaline ingredients such as baking soda or baking soda to the green bean soup. Alkaline ingredients will discolor the mung beans and affect the retention of the emerald green color.

5, rapid cooling: cooked green bean soup can be quickly cooled in cold water after cooking. Quick cooling can help maintain the color of green beans.